When she was a member of the pop trip Wild Orchid in the early 2000s, Fergie began using crystal meth. At her lowest point, "I was [suffering from] chemically induced psychosis and dementia. I was hallucinating on a daily basis," the 42-year-old "A Little Work" singer told the U.K.'s iNews Thursday. "It took a year after getting off that drug for the chemicals in my brain to settle so that I stopped seeing things. I'd just be sitting there, seeing a random bee or bunny."

Fergie believed the CIA, FBI and a SWAT team were tracking her, so she sought refuge at a church. "They tried to kick me out, because I was moving down the aisles in this crazy way, as I thought there was an infrared camera in the church trying to check for my body," she recalled. "I bolted past the altar into a hallway and two people were chasing me. I remember thinking, 'If I walk outside, and the SWAT team's out there, I was right all along. But if they're not out there, then it's the drugs making me see things and I'm going to end up in an institution. And if it really is the drugs, I don't want to live my life like this any more, anyway.' I walked out of the church—obviously, there was no SWAT team. It was just me, in a parking lot. It was a freeing moment."

It's a story Fergie has told time and again—most recently, in a September interview with the London Evening Standard. After walking out onto L.A.'s Wilshire Boulevard, she started "seeing devils everywhere." Yes, she knows that sounds crazy. "I'm very open about what I call my 'dark period.' I went into a church and had this epiphany. It was a crossroads. The drugs that I was taking were making me insane," Fergie said. "I was definitely seeing things and talking to them."

Fergie told Oprah Winfrey in a 2012 interview that she did drugs for about a year before getting sober. "What got me through it was a lot of therapy, soul searching, discovering why I took the drugs in the first place—because that's really what it is," she said, adding that she first experimented with ecstasy before trying crystal meth. At her lowest, she weighed about 90 lbs. "With any drug, everything is great at the beginning—and then slowly, your life starts to spiral."

In her interview with iNews, Fergie added, "The drugs thing, it was a hell of a lot of fun…until it wasn't. But you know what? I thank the day it happened to me. Because that's my strength, my faith, my hope for something better." The fact that she's alive to tell her story today is nothing short of a miracle. "It's so incredible, I know," Fergie said. "I think I must have guardian angels."